1. Field of the Invention
The present invention relates to an imaging apparatus and its control method, and more particularly an imaging apparatus capable of detecting the amount of motion of an object.
2. Description of the Related Art
Conventionally, there is an imaging apparatus which detects an object area based on image data obtained by capturing an image, executes exposure control so as to provide a detected area with correct exposure, and executes focus control so as to bring the detected area into focus. Such an imaging apparatus is discussed in Japanese Patent Application Laid-Open No. 2003-107567.
Further, there is an imaging apparatus which detects information about the motion of an object in order to control object shake and adjusts an exposure control value in response to information about the detected motion. For example, in an imaging apparatus discussed in Japanese Patent Application Laid-Open No. 2007-243250, object shake is controlled by executing control so as to set a fast shutter speed when an object is in motion and a slow shutter speed when an object is not in motion, by viewing the amount of motion of the whole screen.
However, the imaging apparatus discussed in Japanese Patent Application Laid-Open No. 2007-243250 has a drawback. A suitable image can be shot with the imaging apparatus according to Patent Application No. 2007-243250 when the background of the image which a user intends to shoot stands still. However, an intended image cannot be shot when a user intends to capture an image in which the background is streaming or blurred but a moving object is in focus (in what is called a panning shot, using the panning technique where the camera follows the moving object at the same approximate speed that the object is moving at) since the stream or blurring of the background is also stopped.
FIGS. 3A and 3B are diagrams illustrating the drawbacks when exposure control, which controls an object shake using motion detection, is executed.
For example, in the imaging apparatus discussed in Japanese Patent Application Laid-Open No. 2007-243250, when motion is detected, as shown in FIG. 3A, with respect to an image of a moving object, the imaging apparatus can make a person stand still.
However, as shown in FIG. 3B, when a person is moving and it desired to get a shot showing the person in focus but with a blurred background (i.e. a panning shot), even though the user desires to shoot an image with a blurred background, exposure control is executed so that the background does not blur.